Forced air flow air heating furnace



P. MUELLER Filed May 13, 1950 FORCED AIR FLOW AT R HEATING FURNACE Nov.25, 1952 6 83, lN/EA/TOE:

PHUL MUELL ER, I

Patented Nov. 25, 1952 UNITED STATES PATENT OFF] CE FORCED AIR FLOW AIRHEATING FURNACE Paul Mueller, Springfield, Mo., assignor to Paul MuellerCompany, Springfield, Mo., acorporation of Missouri Application May 1-3,1950, Serial No.161;'157 Cl. 126-110.)-

ll-Claims.

.1 This invention relates to space heaters and more particularly to thattype of unit heaters which may be mounted in a suspended positionAnother object of theinvention is to provide a heater of the typementioned in which the burner element discharges through the huboraxially of an axial flow {an arranged to move the air stream lineallyalong the outer wall of the combustion chamber, and through the heatexchanger, which is formed as an extension of the combustion chamber.There is thus provided 'a heating rapparatus which has a high heatingefficiency, and in which there is substantial uniformity and dis.-tribution of the heated gas throughout'the length of the unit.

More particularly, the invention provides a heater which includes at oneend a burner fired by gas or oil, the nozzle of which discharges into acombustion chamber in axial alignment with the burner nozzle, and withthe axis of a fan blower which impels the air stream. The heatexchangeroi the apparatus is arranged in linear extension of thecombustion chamber and is encased within a spaced wall forming theannular air chamber so arranged as to cause the air stream to beimpelled through the apparatus in heat exchange relationship with theouter wall ofthe combustion chamber and of the gas conduit section ofthe heat exchanger. Thus there is provided means for impelling the airstream in an out-of-contact relationship forwardly through the entirelength of the heater. The air chamber discharges into the space to beheated, so that advantage in heating efiiciency is taken of the heattransfer by convection heating through the discharge of the heated airfrom the forward end ofthe heater.

Further detailed advantages of the construction will be apparent fromthe follow-ing description taken in connection with the accompanyingdrawing, in which:

Fig.- 1 is a side elevation of the apparatus with parts broken away inorder to illustrate certain details of the structureof the apparatus;

Fig. 2 is a vertical section throughthe rear portion of the apparatusfor better illustration of the burner, the blower element and a part ofthe combustion chamber;

Fig. 3 is a rear end elevation of the apparatus;

Fig.4 is a horizontal section taken substantially on the. line 4-4 ofFig. 1; and

Fig.5 is a cross section taken substantially on the line 55 of Fig. 1'.

In't'hei embodiment oi. the. invention. illustrated in :the drawing theelements of the apparatusiareencased in an outer-shell l0 of cylindricalform,

At the forward end of the casing llll'zthere is a cone-shaped extensionI Laconstitutinga header into which "may be connected a heated'aircdi's-' charge nozzle 12 or a plurality ofnozzles (not shown) may beconnected into the header if 'de--' sired for additional directdischarge and distribu tion of the heated air :stream into the'space "tobe heated.

The elongated cylindrical form 'of the apparatus adapts it to besuspended in the space to be heated although it will be understood 'thatit may :be otherwise mounted.

In order to provide, however, for the suspension of the apparatus fromthe ceilings oftthe. building space inwhich it maybe used, a suspensionmeans for the unit 'will'ibe' later idea scribed.

The outer flange 2| 'of-lthe'fa'n inlet rin'g- 20 fitted into therearward end of the shell Ill; The form of the fan inlet ring '20 andits location pro-- vide a funnel-shaped intake fo'rair tob'efiimpelledthroughthe heated airconduit, which surrounds thecombustion chamber and the inner or .gas section of the heat exchanger.

The burner element ofthe apparatus is located externally of the rear endof the casing 10. The burner maybe of any desired type, and thehousingof the element is indicated on the drawing by the letter B.

The burner is mounted in such a manner that the nozzle extends coaxiallyofthe casing. l0, so

that it discharges directly into the center of the chamber constitutingthe combustion chamber.

The support for the burner is a bracket which comprises a more orlessL-shaped plate having an upper horizontal section 23 and avertically disposed section 2 1, the lower end of which section 24connects with a sleeve 25, which has spaced ears 26 formed thereon; Thelower edge of the bracket section 24 is positioned between the ears andis removably connected therewith by bolts 21, which pass through theears and through an opening in the lower margin of the plate section 24.The upper edge of the horizontal section 23 of the bracket may have anear 28 formed thereon in order to provide for a connection with asuspension rod indicated at 29.

The burner nozzle 22 is mounted through the sleeve 25 and is. therebysupported.

The sleeve 25 also constitutes a bearing member for a fan. The fanstructure includes a hub member 30, which is mounted on the sleeve 25 byan anti-friction bearing 3|. A series of radial blades 32 are carried bythe hub, and so arranged as to impel the air stream forwardly in alineal direction.

The fan is driven by a motor M which is supported on a mounting plate 35carried by the upper wall of the bracket 2324. The base ofthe motor isadjustable, providing for belt ten.- sioningsby bolts 36.

The motorshaft has mounted thereon a pulley 31. The hub of thefan hasconnected thereto a pulley 38. A belt connection 39 between said g tothe exterior of the Wall 45 of the combustion pulleys, and which extendsthrough a slot in the outer shell l0, serves as a powerdrive for saidfan.

The inner end of the sleeve 25 is formed to provide an annular flange 40which is bolted to a head plate 4| of the outer casing of the combustionchamber by bolts 42. The inner end of the burner nozzle extends throughthe head plate M, and discharges into the combustion chamber so that thecombustible gas mixture travels forwardly through the combustion chamberin a linear direction.

The combustion chamber includes an outer cylindrical wall formedintegrally with the head plate 4|, and an inner cylindrical wall G6, therear end of which is spaced from the head plate 4| The inner wall 46 isformed from a heat resistant material such as stainless steel, so thatthe outer wall 45 is protected from the high heat of the gas flame.

It will be notedthat since the burner discharges along the axis of thecombustion chamber that the impingement of the hot flame directlyagainst the walls is minimized, and that thereby hot spots will notdevelop, but that the heat transfer from the combustion zone of theheater 9 to the air chamber around the combustion chamber is efficientlyprovided for.

The forward end of the combustion chamber connects into a series oftubes which terminates near the forward end of the heater unit, and isof a substantial length to provide for the travel of the hot gases inheat exchange relation with the outer annular chamber through which theair stream is forced by the blower.

The design of the heat exchanger per se is not a part of the presentinvention, but a satisfactory form thereof has been indicated in thedrawing.

The inner element through which the hot gases move comprises a generallycylindrical wall 50, which opens into a series of radial tubes, whichproject into the air conduit. A cylindrical wall 5! spaced from the wall50 provides the outer wall of the air conduit of the heat exchanger.Since the air stream traverses the surface of the tubes through whichthe heated gases move forwardly into a header at the forward end of theinner element of the heat exchanger, there is provided a substantiallength of travel of the air stream with the heat exchange surface of thetubes through which the heated gases are required to travel, thuseificiently heating the air before it discharges into the space to beheated.

A vent pipe 53 is provided at the forward end of the gas section of theheat exchanger to evacuate the gas stream after it has traversed thelength of the gas conduit section of the heat exchanger.

It is to be understood that the air stream discharges into the sectionof the casing II and is forced outwardly through the nozzle l2.

The heater is designed in such a manner as to be conveniently assembledby providing supports and connections for the several elements in theirproper relationship, as well as providin means for the installation ofthe unit preferably in suspension as heretofore mentioned.

In order to provide a passage in front of the fan so that the air streamwill enter the heated 7 air conduit, the forward 'end of the air inletring 20 is connected with the outer wall 45 of thecom bustion chamberwhere ,itj oins theheader plate 4| by a series of spaced metal straps60, which may be welded to the margin of the plate 20 and chamber. Thisprovides for an air space forwardly of the fan, which connects into theair chamber around the combustion chamber.

The outer wall of the combustion chamber is supported in spacedrelationship and to the outer shell by a radial series of rods 6|, asindicated in Fig. 5 of the drawing.

In order to provide for mounting the heater in suspension, a series oflongitudinally spaced ring members 62 are welded, or otherwise securedto the inner wall of outer casing Ill. Welded or otherwise attached toeach of said rings, are hanger clips 63 which project outwardly throughslots 64 provided in casing I0.

In order to give strength to the support of the various elements by therods 6!, it is preferred to. mount them so that their outer extremitiesare connected to the inner wall of the rear ring 52, as has beenindicated particularly in Fig. 5.

In Fig. 1 there are indicated at B5 suspension rods, which have hooksformed at their lower end to engage into the openings in the hangerclips-63.

It will now appear from the foregoing description that there is provideda heater unit that accomplishes the objectives as set out in the fore:going part of this specification.

While'I have described in detail certain of the structure,'it should beunderstood that the invention is not limited except as expressed in theclaims.

What is claimed is:

1. In a heater of the kind described, a cy1in drical combustion chamber,a burner unit having a nozzle discharging linearly into said chamber, acasing surrounding and space-d from said combustion chamber andproviding an annular air chamber around said combustion chamber, thecasing having an air inlet positioned to admitv external air to said airchamber at the same end, as said nozzle and being further provided withan outlet, and a fan mounted for rotation on and supported by saidnozzle to impel an-air stream through said air chamber.

2. In a heater of the kind described, a cylindrical combustion chamber,a burner unit having a nozzle discharging linearly into said chamber, acasing surrounding and spaced from said combustion chamber and providingan annular air chamber around said combustion chamber, the casing-havingan air inlet positioned to admit external air to said air chamber at thesameend as said nozzle and being further provided with an outlet, a fanmounted for rotation on and sup-- ported by said nozzle to impel an airstream through said air chamber, and a heat exchanger positionedforwardly of said combustion chamberincluding a gas chamber in heatexchange relation with the air chamber. 7

3. In a heater of the kind described, a tubular structure constituting acombustion chamber, a

burner unit having a nozzle discharging linearly into said chamber alongthe axis thereof, a tubular casing spaced from and around saidcombustion chamber forming an air chamber outside the combustionchamber, the casing having an air inlet to admit external air at thesame end of said air chamber as said nozzle and being further providedwith an outlet, and a fan mounted for rotation on and supported by saidnozzle to impel an air stream through said air chamber.

4. In a heater of the kind described, a tubular structure constituting acombustion chamber, a burner unit having a nozzle discharging linearlyinto said chamber along the axis thereof, a tubular casing spaced fromand around said combustion chamber forming an air chamber outside thecombustion chamber, the casing having an air inlet to "admit externalair at the same end of said air chamber as said nozzle and being furtherprovided with an outlet, a fan mounted for rotation on and supported bysaid nozzle to impel an air stream through said air chamber, a heatexchanger formed as an extension of said combustion chamber and withinsaid air chamber in heat exchange relation thereto.

5. A heater of the class described, including an outer elongated casing,an inner elongated casing of less cross section than said outer casinghaving a header closing the inner end thereof, supporting means tomaintain said casing in spaced relationship and thereby to form an outerair chamber having an inlet and an outlet around the inner casing, aburner unit having a nozzle entering through said header to said innercasing, an air inlet ring fitted into the inner end of said outer casingat the same end as said nozzle constituting the air inlet to said airchamber, and a 'fan mounted within said inlet and supported by saidnozzle arranged to impel an air stream longitudinally through said airchamber in heat exchange relationship with the wall of said innercasing.

6. A heater of the class described, including an outer elongated casing,an inner elongated casing of less cross section than said outer casinghaving a header closing the inner end thereof mounted Within said outercasing, the space between said casings forming an air chamber having aninlet and an outlet and said inner casing constituting a combustionchamber, a burner unit having a nozzle entering through said header tosaid combustion chamber, an air inlet ring fitted into the inner end ofsaid outer casing at the same end as said nozzle constituting an airinlet passage to said air chamber, and a fan mounted within said inletand supported by said nozzle arranged to impel an air streamlongitudinally through said air chamber in heat exchange relationshipwith the wall of said inner casing.

7. A heater of the class described, including an outer elongated casing,an inner elongated casing of less cross section than said outer casinghaving a header closing the inner end thereof, said casings being inspaced relationship and thereby to form an outer air chamber around theinner casing and a combustion chamber, a burner unit having a nozzleentering through said header to said inner casing, the outer casinghaving an air inlet at the end of said outer casing to admit an airstream to said air chamber at the same end as said nozzle and beingfurther provided with an outlet, and a fan mounted within said inlet andsupported by said nozzle arranged to impel an air stream longitudinallythrough said air chamber in heat exchange relationship with the wall ofsaid inner casing.

8. In a heater of the class described, the combination of means forforming a combustion chamber comprising inner and outer elongatedtubular members arranged concentrically, a tubular outer casing spacedfrom said combustion chamber to provide an annular air passage in heatexchange relationship throughout the length of said combustion chamber,one end of said air passage having an air inlet at one end thereof andthe other end having an air outlet, a burner unit having a tubularnozzle discharging into said combustion chamber adjacent the air inletend axially thereof, and a fan having a hub member mounted for rotationon said nozzle, said hub member carrying radial blades to impel an airstream through said air passage.

9. In a heater of the class described, the combination of means forforming a combustion chamber comprising inner and outer elongatedtubular members arranged concentrically, a tubular outer casing spacedfrom said combustion chamber to provide an annular air passage in heatexchange relationship throughout the length of said combustion chamberone end of said air passage having an air inlet at one end thereof andthe other end having an air outlet, means supporting said tubularmembers in spaced concentric relation, a burner unit having a tubularnozzle discharging into said combustion chamber axially thereof adjacentsaid air inlet end, and a fan having a hub member mounted for rotationon said nozzle said hub member carrying radial blades to impel an airstream through said air passage.

10. In a heater of the class described, the combination of means forforming a combustion chamber comprising inner and outer elongatedtubular members arranged concentrically, a tubular outer casing spacedfrom said combustion chamber to provide an annular air passage in heatexchange relationship throughout the length of said combustion chamberone end of said air passage having an air inlet at one end thereof andthe other end having an air outlet, 2. burner unit having a tubularnozzle discharging into said combustion chamber axially thereof adjacentsaid air inlet end, a fan having a hub member mounted on said nozzle,said hub member carrying radial blades to impel an air stream throughsaid air passage, and supporting means including hanger clips adapted tosupport the heater in suspension.

11. A furnace construction including an elongated, closed, tubularcombustion chamber, a head at one end and a flue outlet at the other, atubular member connected through the head, and extending outwardly fromthe head, the tubular member being of a size to receive a burner headfor directing a combustible mixture into the combustion chamber, abearing outside the tubular member, a fan mounted on the bearing torotate about the tubular member and direct air against the combustionchamber, casing means surrounding the combustion chamber provided withan inlet at one end adjacent the burner to receive the air from the fanand confine it around the chamber, the casing having an opening at theend of the combustion chamber remote from the fan, for the discharge ofheated air.

PAUL MUELLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,363,168 Findley Nov. 21, 19442,386,807 Leslie Oct. 16, 1945 2,395,417 McCollum Feb. 26, 19462,417,185 Williams Mar. 11, 1947 2,417,315 McCollum Mar. 11, 19472,517,398 McCollum Aug. 1, 1950

